Ridderkerk (Dutch pronunciation: [ˌrɪdərˈkɛr(ə)k] ^ⓘ) is a town and municipality in the western Netherlands, in the province of South Holland. The municipality had a population of 46,671 in 2021 and covers an area of 25.26 km² (9.75 sq mi) of which 1.54 km² (0.59 sq mi) is covered by water.

The municipality of Ridderkerk also includes the following towns, villages and townships: Bolnes, Oostendam, Rijsoord and Slikkerveer.

Ridderkerk has a museum called De Oudheidkamer, covering the history of the town. The centre of Ridderkerk has a central square for events and there is a theater.